This is really sad. She was such a great talent whose life was destroyed by demons & drugs. Horrible loss for all. I can barely believe she’s just 22 years old when she sang this. http://www.youtube.com/watch?v=uXFliKZruXE

Most drugs can kill you at any age, as long as you do enough of them or mix them the wrong way. People have OD’d a lot younger than 48.
As for Whitney, a very talented musician, but maybe not so good when it came to other choices and decisions.